Turn indicator



c. As. DRAPER lTURN INDICATOR June 8, 1943.

Original Filed April 19, 194D 2 Sheets-Sheet ll PER, 4M

' June', 1943. Qs, DRAPER Re. 22,330

TURN INDICATOR q origina.; Ened-Api-ilrls, 1940 2 'Smets-sheet 2 mvENToR #E ,aff A'/--Asz/a n WL s,

' rate springs.

Ressued June 8,1943

t UNITED STATES PATENT o Re. 22,330 F F I C E TURN INDICATOR Charles S. Draper, Newton, Mass., assignor to Sperry Gyroscope Company. Inc., N. Y., a corporation of New Yorkl Brooklyn,

Original No. 2,291,612, dated August 4, 1942, Serial No. 330,481, April `19, 1940. Application for reissue March 15, 1943, Serial No. 479,299

I Cl. 33-204) 23 lams.

This invention relates to two-degree of freedom gyroscopes, such as widely employed to indicate the rate of turn of the vehicles on which they are mounted or, in fact, the rate of angular motion around any axis, such as rate of roll or-rate of pitch as well as rate of turn. y Such gyroscope-s have only one pivotal axis besides the axis of spin and it is the principal object of this invention to improve the formV of bearing employed for this axis. The present practice is to provide ball bearings for this axis and to employ, in addition, coi1 form of damper.

tension springs for opposing the precession' of the gyro so that the amount of precession from the neutral position is approximately proportional to the rate of turn.

Abcording to my invention, I propose to replace both the tension coil springs and the ball bearings by a new form of pivotal'support which performs the function of both the bearings and the springs in a .superior manner, and which is cheaper to manufacture and will stand up better under vibration and rough usage. According to my invention, I provide a precession axis for the turn gyroscope by supporting the horizontal trunnions at both ends solely by spring means which not only pivotally support the gyroscope for precession about this axis, but also prov-ide the yieldingfcentralizing means for which purpose it was previously necessary to provide sepau Applicants spring means may comprise a plurality of relatively stiff, hat springs symmetrically arranged around and spaced from each trunnion, and anchored at their outer ends to the casing with their inner or free ends connected to said trunnions by radially extending members which may also be in the form of hat springs cf greater flexibility. In addition. with my form oil spring the amount of precession oi the gyroscope is more nearly proportional to the rate of turn through large angles,

A further object achieved by my invention is the improvement of the damping means employed for rate of turn gyroscopes, by which the damping means not only strongly damps the precession of the gyroscope, but also suppresses vibration of '4 the spring-supported rotor bearing frame in any direction and acts as a cushion to prevent vlbrations of the support from reaching the gyroscope.

Referred to the drawings, showing the preferred form of my invention:

Fig. l is a vertical section through a rate of turn gyroscope with my improved pivotal support therefor.

Fig. 2 is a face View of the same.

Fig. 3 is a rear elevation of the same.

Fig. 4 is a diagram showing the deflection of the springs caused by precession of the gyro and also showing aslightly modied form of the invention. I

Fig. 5 is avertical section through a modified form of rate gyroscope.

Fig. -6 is a face view of one of the clamping discs used thereon.

Fig. 'I' is a sectional detail taken approximately on line 1-1 of Fig. 5 and showing the universal coupling between the gyroscope and pointer.

Fig. 8 is an end elevation showing an Improved form of damper on the leaf springs.

Fig. 9 is a similar view showing a still different Fig. 10 is a sectional detail taken on line Ill-III of Fig. '9.

The angular rate gyroscope'y shown in Fig. 1

is. shown as mounted within a casing I. The

gyro rotor 2 is shown as air spun, as by means of nozzles 3 and 4. The rotor is shown as journaled in normally horizontal ball bearings 5 within the rotor bearing ring ory frame 6, which in turnis journaled on a horizontal axis atrlght angles to the spin axis. I provide freedom about saidhorizontal axis by supporting the ring B by means of a plurality of relatively stiff flat springs II, II', I2, I2 symmetrically arranged around each trunnion 8, 8' and' connected to the trunnion by radially extending portions 9, I0, which may'also be in the form of flat springs which. however, are much thinner and more ilexible than the springs II, II", I2, I2'. Springs 9 and I0 are shown as extending substantially at right angles to the springs II, II', I2 and I2' and are shown as fastened through slots in the trunnions B, 8'.' in which they are tightly clamped at their center. At their outer ends, members 9 and IIJ are tightly clamped to the free ends of 'the springs II, II', I2, I2', which are shown as bent at an angle for this purpose. Metal clamps or clips IIII may be-used to bind the springs together at this point.` Theouter ends of the springs II, II', I? and I2 are tightly clamped in brackets I 3 secured to or projecting from `the case. Preferably, also, these springs are placed under slight bending stress so as to place the springs or tension members 9 and I0 luider tension to supportV the weight of the gyro assembly against jolts and jars in any direction. This is illustrated by showing a slight convex bow in the springs II, II', I2, I2', which exert the major portion ci the centralizing force onl the gyroscope. In order to damp out up-and-down and lateral vibrations of the system, I preferably enclose the springs II, II', I2, I2 with sleeves I8 ol' some suitabley damping material such as an oil soaked sponge, soft telt, viscose or the like, which act as effective dampers.

' Damping of the precessional movements of the gyroscope may be accomplished by some form ofv dash pot or other liquid damper, such as a bladed arm 30 secured to ring E which dips into a small liquid container 3|' on the interior of casing I.

The trunnion is also shown as having a pivots about the Yshown in Fig. 3 with the gyro in its neutral or central position. The full lines indicate the form assumed by the springs when the gyro precesses in a counterclockwise direction through a small angle. At first the upper portion of the springs 9 and Ill are bowed to the left and the lower portion to the right, with the result thatY the precession of the gyroscope is thus yieldingly opposed by this weak bending force. As the precession increases, an increasing inward pull is exerted on the ends of the stiff springs II, il',

I2, I2', which exert the major portion of the centralizing force onthe gyroscope, thus pulling them inwardly into the full line position. This results ina-n increased. yielding force opposing v' the precession. By calculation and experimentation I have found that the forces thus secured give a more uniform precession of the gyro for increasing rates of turn than do the simple coil springs of the prior art, partly because the amount of precession against a uniform spring is not constant due to the fact that as the, gyro precesses through large angles, its spin axis becomes more and more coincident with the axis of turn, resulting in a decrease in the precession force developed. v

In addition to this advantage is the fact that I have eliminated entirely the usual ball bearing precession axis, eliminating the troubles therewith due to wear and imperfections of the balls, and also static friction incident to all bearings. l

It is obvious that my invention may assume many forms. For instance, instead of making the springs 9, .II and II' and III, I2 and I2' in three pieces each. each set may be formed of one piece merely by bending each spring through a substantial angle at intermediate points between its mid point and both ends to form elbow portions clamped at their free ends by brackets I3 to casing if desired, giving the end portions of each spring a different temper from the middle portion to` provide a greater stiffness in the end portions.

Figs. 5 to 10. inclusive, show further modifications of my invention. In this form, only one spinning jet 3 is shown, the air jet engaging the wheel near the horizontal axis of precession 8 8'. In@ this form also, improved damping means are` provided for oscillations or vibratori! movements of the gyroscopic system in all planes, namely, damping means for rotational and linear oscillations and vibrations in all planes.

To damp the precession of the gyroscope, I have shown secured at least to one trunnion 8, and preferably to both trunnions 8 and l', a thin disc 2li of sheet metal which is preferably provided with aplurality of holes 2i and connected slots 22. in a stationary casing 23 in which oil is placed to a level preferably somewhat below that of the axis 8-82 `Precessilon of the gyroscope will therefore be resisted by the liquid drag on the disc while the'holes and slots in the disc tend to prevent any sticking of the disc against the f walls oi the container by preventing the formation of` a seal. As shown in Fig. 5, clearance is I as shown in Fig. 4 and,

ytion of the easings.

. allowed between the trunnions 8 and 8 and the .casings 23 and 23' and escape oi' oil is avoided by providing the trunnions where they entend through the casings with conical-*shaped collars 31 and 38 so that any oil thatfmay get above the trunnion will drain back into the lower por- This form of damper also assisA in preventing endwise translation or sudden displacement of frame 6 in casing I. since the'iiat discs oppose and strongly damp sudden relative displacements of this character.

For damping translatory vibrations of the trunnions, i. e., up-and-down and lateral, I have in this instance used metal U-shaped pieces 24 fixed to the hou-sing; having therein a piece or pieces of soft felt, viscose or the like, 25, which are held against, two sides of the laterally ei;- tending portions II A- and I2 of the spring supports. 'When such material is soaked in oil, it provides an excellent damper for suppressing linear vibrations.

For suppressing rotary vibrations or quick pe riod oscillations, I have shown a sheet metal frame 26 in the form of a cross, the ends of which are folded over to enclosesimiiar pieces- 25 of soft material to enclose a portion of the radial springs il and I0 (see Figs. 9 and 10).

' The cross frame 2G is loosely mounted on the Each disc is shown as enclosed shaft B so as not to oppose its rotation, but to merely suppress vibrations causing bending of the strips 9 and III. The same" purpose is accomplished in Fig. 8 by blocks 35 similar to 24 but unconnected to the casing so that they suppress only bending ofthe strips.

In this case, I have shown the pointer or other indicator I6 mounted on a shaft 21, which is rotated from a gear sector 28 secured to 'a small cross shaft 29. The shaft 29, in turn, 'is rotated.

from a shaft 30 coaxial with shaft 21 and trunnionB by means of a pin and slot connection 3i. The shaft 30, in turn', is journaled independently of the trunnion 8' and has a universal connection 32 thereto so that the radial move-l ments of the trunnion 8 will not place any load on the bearings of the shaft 30. As shown in Fig. 7, said universal connection may be in the form of a central thin flexible ring 45 secured by two spaced rivets 46 `and IB' to a first ring I 1 41 and secured by two spaced rivets 4B on the other side thereof and spaced 4 from said other Vrivets to a third ,ring 49. The gyro trunnion B' is shown as secured to the first ring 41 while the shaft 30 is secured. to ring 49. Thus, a lim- .ited universal connection is provided between the trunnion and shaft. The pointer I6 is thus independently mounted from the gyroscope and at the same time its movement ls greatly magnied. In this way, the gyroscope may be restrained to comparatively small precession angles without sacrificing the large scale movement of the pointer. 4 scope dlmishes when it precesses through a large angle,I achieve in this manner a more accurate indication-of rate of turn through a wider range than possible in the present types of rate of turn indicators.

As many changes could be made-in the above construction and many apparently widely different embodlments of this invention could be made without departing from the scope thereof.

it is intended that all matters contained in the above description or shown`in the accompanying drawings shall-be interpreted as illustrative and not in 'a limiting sense.r

Since the accuracy of the gyroi sasso 3 Having described my invention, what` I claim ber of lesser stillness secured to the adjacent and desire to secure by Letters Patent .isz' f rame of 'the gyroscope at a mid point of said.

l. In an angular rate gyroscope, a rotor, a second spring, bearing frame within which said rotor is'mounted for spinning about an axis an outer casing, .and means for pivotally mounting said frame in` lsaid casing for precession about a second axis, including a leaf spring extending in both directions from said frame and clamping means for securing the outer ends of said spring to said 1' each end of said second spring being secured to an inner end of one of said iirst 5 named pair respectively, said springs serving means therefor, and damping material clamped latory and translatory vibrations.

casing for both pivotally supporting the .frame 8. An angular Yrate gyroscope comprising an and yieldingly opposing the precession of the gyouter hollow casing, a at spring member ad -roscope in either direction from its normal posijacent each end of said casing secured at both tion.

. ends to the interior of said casing and having 2. An angular rate gyroscope as claimed in 1.', the middle portion of each extending radially claim l, in which said spring means includes a across the casing, a precession trunnion of the nat spring clamped at its mid point to said gyroscope adjacent each end of the casing to frame, bent at a substantial angle at a point which the mid portions of said springs are rebetween said mid point and its ends and clamped specti-vely clamped, said spring servingboth to at both ends to said casing.

support said trunnion and provide yielding cen- 3.`An angular rate gyroscope comprising an tralizing means therefor, and a rotatable indiouter casing, a flat spring member adjacent each cator pivoted independently of said gyroscope end of said casing secured at both ends to the and connected thereto by multiplying gearing for interior thereof and having the middle portion .of showing the rate of turn.

each extending radially across the casing, and 9. In an angular rate gyroscope, a rotor, a a procession trunnion of the-gyroscope adjacent bearing frame within which said rotor is mounteach end of the casing to which the mid portion ed foi-.spinning about an axis, an outer casing, of said spring is clamped, said spring serving means for pivotally mounting said frame in said both to support said trunnion and provide yieldcasing for precession abouta second axis without ing centralizing means -therefor. a bearing including spring means extending be- 4. An angular rate gyroscope comprising an tween said frame and said casing for both pivouter casing, a pair of flat spring members adotally supporting the frame and yieldingly opposjacent each end of said casing secured at the ing the precession of the gyroscope in either diouter ends to the interior thereof, a member rection from its normalposition,arotatable indiof each pair being bent substantially at right cator pivoted independently of saidgyroscope, angles at its inner end, and a l.second or conan independently pivoted shaft, a universal joint connected between said second shaft and said gyroscope and multiplying gearing between said point and at both ends to the inner end of said shaft and said pointer. iirst named pair, said members serving both 40 10. In an angular rate gyroscope, a rotor, a to support said gyroscope about its precession bearing frame within which said rotor is mounted axis and to provide yielding centralizing means 'for spinning about an axis, an outer casing, and therefor. y means for pivotally mounting said frame in said 5. In an angular rate gyroscope, a rotor, a casing for precession about a second axis at an bearing frame within which said rotor is mounted angle to said axis of spin, including a plurality for spinning about an axis, an outer casing, of symmetrically arranged leaf springs extending means for pivotally mounting said frame in said between said frame and said casing for both pivcasing for precession about a. second axis withf otally supporting the frame and yieldingly opout a bearing, comprising only a plurality of posing the procession of the gyroscope in-either springs extending between said frame and said ro direction from its normal position. casing in a plurality of directions for both pivot- 11. An angular rate gyroscope comprising an ally Supporting anduding he frame and yieldouter casing, a, plurality of symmetrically aringly imposing the precession of the gyroscop'e ranged members including iiat springs adjacent in eithery direction from its normal position, and at least one end of said casing, each member damping means engaging Said spring mea-ns fOr .55 being secured at both ends to the interior of said suppressing vibrations of the gyroscope.

casing `and having its middle portion extending 6. In an angular rate gyrOSCOPe, a 101701', a radially across the casing, and a precession trunbeS-ring frame Within Which Sad TOOI 1S mounted l nion of said gyroscope adjacent said end of the for spinning about an axis, an outer casing,

means viorpivotally mounting said frame in aid Go bers are clamped, said members serving both to Y u tralizin means he e prings extending between said frame and said 12. I an angina; glt'e gyroscope a rotor a aging in a plurality of directions for both pivot' bearing frame within which said rotor is mounted ily supporting and guiding the frame and yieldf Y b gly Aopposing the procession of the gyroscope or slmmng a out a n axlsf an Outer casmg means n either direction from its normal position, and for plvotau? mmmtmg Sad frame 1F Said casing iquid damping means acting about the precesfor Precessmn aPout a Second aXlS Without a ion axis for suppressing precession. bearing COmPIISmg only a plurality of springs 7. An angular rate gyroscope comprising an elftendlng between Sald frame and said casing in uter casing, a pair of flat spring members addm'erent directlons fOI' ent each end of said casing secured at their and guiding the fra uter ends to the interior of said casing, a memlJh@ DreCeSSiOn of the er of-each pair being bent substantially at right tion from its normal u les at its inner end, a second flat spring memboth to support said gyroscope about its precession axis and to provide yielding centralizing on each spring member to suppress both oscil- 4 i n sasso.

\ and damping means ior suppressing translatory vibrations of said frame within said casing.

13. In an angular rate gyroscope, a rotor, a bearing frame within which said rotor is mounted for spinning about an axis, an outer casing,A means for pivotally mounting said frame in said casing `for precessionA about a second axisv without a bearing, comprising only a vplurality of springs extending betweensaid frame and said casing in different directions for both pivotally supporting and guiding the frame and yieldingly opposing the precession of thegyroscope in either direction from its normal position, a disc on s aid frame for turning therewith, and a closely fitting Aliqid container therefor secured to. said casing whereby the precession is damped and endwise displacement suppressed.

14. In an angular rate i gyroscope, a rotor, a bearing frame within which said rotor is mounted for spinning'about an axis, an outer casing, means for pivotally mounting said frame in said casing for precession about a second axis without a bearing, comprising a plurality ofsprings extending between said frame and said casing indifferent directions for both pivotally supporting and guiding the frame and yieldingly opposing the precessaid frame for both pivotally supporting the frame and yieldingly opposing the procession oi' the gyroscope in either direction from its normal position.

. casing 4for precession about a second axis without sion of the gyroscop in either direction from its normal position, damping means for the precessional movements of said ramadamping means for suppressing translatory vibrations of ,said frame within said casing. a rotatable indicator pivoted independently of said gyroscope `in said casing, and a universal connection between said f indicator and gyroscope.

15. In an angular rate vgyroscope, a. rotor, a

bearing frame within which said rotor is mounted for spinning about an axis, an outer casing, and

means for pivotally mounting said frame in said casing for precession about a second axis, including laterally extending trunnions on said frame,

a leaf spring clamped in each trunnion and exv tending radially therefrom and having an outer end bentvat asubstantial angle into said radially extending portion to form an elbow portion, and means clamping the outer end of each elbow to said casing. i

16. In an angular rate, gyroscope, a rotor, a

bearing frame in which said rotor is mounted for v spinning about an axis, trunnions on said bear` ing frame, and spring means both for pivotally supporting .said frame for procession in said casing and for yieldingly opposing precession includ` ing a leaf spring clamped in a trunnion and extending radially therefrom vand having its outer end bent at asubstantial angle to 'form an elbow portion, and means clamping the outer end oi' said elbow portion to said casing, whereby procession is opposed both by iiexing of said radial portion of the spring and by bending said elbow portion of said leaf spring'.

17. An angular rate gyroscope as claimed in claim 16 wherein said leaf spring extends radially yin both directions from said trunnions and has both ends bent laterally in opposite directions forming two elbows clamped to said casing. 18. In an angular ratey gyroscope, a rotor, a

i bearing frame within which said rotor is mounted for spinning about an axis, an outer casing, and means for pivotally mounting said frame in said casing for precession about a second axis at i an angle to said axis of spin, including a plurality of leaf springs placed symmetrically around said precession axis and connected at their outer portions to said casing and 'atthe free portions to a bearing, comprising only4 a plurality of springs extending between said frame and said casing in different directions for both pivotally supporting and guiding the frame and yieldingly opposing the precession of the gyroscope in either direcviscous liquid filling thelower portion only of said container, whereby precession is damped and endwise displacements suppressed andthe spilli ing of the liquid avoided.

20. An angular rate gyroscope as claimed in claim i8, wherein said elbow portion of said leaf spring is so clamped to the casing as to place said radially extending portion under tension.

21. In an angular` rate gyroseope, a` rotor, a bearing frame .within which said rotor is mounted forspinning about an axis, an outer support, means for pivotally mounting Isaid frame in said support for precession aboutl a second axis without a bearing, comprisingonly spring means extending between said frame and said casing on each side of said frame for both pivotally supporting and guiding the frame and yieldingly opposing the precession of the gyroscope in either direction from its normal position, and damping means acting about said precession axis for both damping the precessional movements 'of said frame and suppressing relative vibrations of said frame and said support.

22. In an angularrate gyroscope, a rotor, a y

` placement suppressed.

23. In an angular rate gyroscope, a rotor, a bearing frame within which said rotor is mounted for spinning about an axis, a support, means for pivotally mounting 'said frame in said support for precession about a second axis without a` bearing, comprising only spring means extending between said frame and said casing on opposite sides of said frame for both pivotally supporting and guiding the frame and yieldingly `opposing the precession of the gyroscope in either direction from its normal position, a disc on said `frame for-turning therewith, a closely fitting liquid container.Y therefor secured to said casing,

and a viscous liquid iilling the lower portion only of said container, whereby precession is damped and vibrations absorbed between the frame and support and the spilling of liquid is avoided.

CHARLES S. DRAPER. 

